Fix versioning serializer

Author: wojtek-t

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/versioning/versioning.go

@@ -199,23 +199,22 @@ func (c *codec) Encode(obj runtime.Object, w io.Writer) error {
 		return err
 	}
 
+	objectKind := obj.GetObjectKind()
+	old := objectKind.GroupVersionKind()
+	// restore the old GVK after encoding
+	defer objectKind.SetGroupVersionKind(old)
+
 	if c.encodeVersion == nil || isUnversioned {
 		if e, ok := obj.(runtime.NestedObjectEncoder); ok {
 			if err := e.EncodeNestedObjects(runtime.WithVersionEncoder{Encoder: c.encoder, ObjectTyper: c.typer}); err != nil {
 				return err
 			}
 		}
-		objectKind := obj.GetObjectKind()
-		old := objectKind.GroupVersionKind()
 		objectKind.SetGroupVersionKind(gvks[0])
-		err = c.encoder.Encode(obj, w)
-		objectKind.SetGroupVersionKind(old)
-		return err
+		return c.encoder.Encode(obj, w)
 	}
 
 	// Perform a conversion if necessary
-	objectKind := obj.GetObjectKind()
-	old := objectKind.GroupVersionKind()
 	out, err := c.convertor.ConvertToVersion(obj, c.encodeVersion)
 	if err != nil {
 		return err
@@ -228,10 +227,7 @@ func (c *codec) Encode(obj runtime.Object, w io.Writer) error {
 	}
 
 	// Conversion is responsible for setting the proper group, version, and kind onto the outgoing object
-	err = c.encoder.Encode(out, w)
-	// restore the old GVK, in case conversion returned the same object
-	objectKind.SetGroupVersionKind(old)
-	return err
+	return c.encoder.Encode(out, w)
 }
 
 // DirectEncoder was moved and renamed to runtime.WithVersionEncoder in 1.15.

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/versioning/versioning_test.go

@@ -102,6 +102,28 @@ func TestNestedEncode(t *testing.T) {
 	}
 }
 
+func TestNestedEncodeError(t *testing.T) {
+	n := &testNestedDecodable{nestedErr: fmt.Errorf("unable to encode")}
+	gvk1 := schema.GroupVersionKind{Kind: "test", Group: "other", Version: "v1"}
+	gvk2 := schema.GroupVersionKind{Kind: "test", Group: "other", Version: "v2"}
+	n.SetGroupVersionKind(gvk1)
+	codec := NewCodec(
+		nil, nil,
+		&mockConvertor{},
+		nil,
+		&mockTyper{gvks: []schema.GroupVersionKind{gvk1, gvk2}},
+		nil,
+		schema.GroupVersion{Group: "other", Version: "v2"}, nil,
+		"TestNestedEncodeError",
+	)
+	if err := codec.Encode(n, ioutil.Discard); err != n.nestedErr {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if n.GroupVersionKind() != gvk1 {
+		t.Errorf("unexpected gvk of input object: %v", n.GroupVersionKind())
+	}
+}
+
 func TestDecode(t *testing.T) {
 	gvk1 := &schema.GroupVersionKind{Kind: "Test", Group: "other", Version: "blah"}
 	decodable1 := &testDecodable{}
@@ -311,6 +333,28 @@ func (c *checkConvertor) ConvertFieldLabel(gvk schema.GroupVersionKind, label, v
 	return "", "", fmt.Errorf("unexpected call to ConvertFieldLabel")
 }
 
+type mockConvertor struct {
+}
+
+func (c *mockConvertor) Convert(in, out, context interface{}) error {
+	return fmt.Errorf("unexpect call to Convert")
+}
+
+func (c *mockConvertor) ConvertToVersion(in runtime.Object, outVersion runtime.GroupVersioner) (out runtime.Object, err error) {
+	objectKind := in.GetObjectKind()
+	inGVK := objectKind.GroupVersionKind()
+	if out, ok := outVersion.KindForGroupVersionKinds([]schema.GroupVersionKind{inGVK}); ok {
+		objectKind.SetGroupVersionKind(out)
+	} else {
+		return nil, fmt.Errorf("unexpected conversion")
+	}
+	return in, nil
+}
+
+func (c *mockConvertor) ConvertFieldLabel(gvk schema.GroupVersionKind, label, value string) (string, string, error) {
+	return "", "", fmt.Errorf("unexpected call to ConvertFieldLabel")
+}
+
 type mockSerializer struct {
 	err            error
 	obj            runtime.Object